Cortical implant

A cortical implant was a device used to interface directly with the mind of a humanoid.

The Breen employed a type of cortical implant to probe the minds of prisoners, with unpleasant mental and physical side effects. These devices were used to interrogate Worf and Ezri Dax in late 2375. (DS9: "'Til Death Do Us Part")

In 2376, The Doctor removed the microcortical implants of former drones Lansor, P'Chan, and Marika Wilkarah at their request, breaking the neural link between them that had been created by Seven of Nine years earlier. However, the neural link had become tied to their higher brain functions, and so they survived no more than a month afterwards. (VOY: "Survival Instinct")

Later that year, Seven of Nine experimented with downloading data collected by USS Voyager directly into her cortical implant through her alcove. However, there was too much information for her brain to process, and she began drawing spurious connections and forming conspiracy theories as a result. (VOY: "The Voyager Conspiracy")

The cortical implant in Borg drones may be the same device as the cortical node.